the lisp in question studies the entity picked (nentsel) and grabs the
z-data accordingly.
if it is a 3dface then it extracts the list of points, eliminates duplicates
if ti is a text or mtect it converts the value to a z coordinate and
searches for other entities of similar layers/values etc
if it is an attribute it searches for similar blockas and attributes and
does the same thing
if it is a 3dpoint it simply extracts it
splines/plines with text near them for height are converted into data points
at an equal interval along the spline /plines
if the spline/plines z is constant it will search for text near the points
and if only one found attempt to extract z info - otherwise it pauses and
asks the user to enter a z or indicate which object has the appropriate z
value for that entity.
output is to a x,y,z or z,x,y file, or create 3dpoints etc
we received a 3dface representation of mount royal near mcgill uniuversity
that contain about 40,000 3dfaces. the user was able to create the .txt
x,y,z file in seconds.
--
TDP
First things first, but not necessarily in that order.
The Doctor
wrote in message news:6341099@discussion.autodesk.com...
Dear Vector2
What our friend is saying about a Lisp routine that does the job of creating
the topography is true. I wrote one for me, too, and I explain its use to my
students in my courses. Revit provides 3 ways of making a site: 1) By
manually adding points with elevations , 2) By importing a drawing, and 3)
By reading a list of points.
The method that you are proposing (tracing over) has to do with option # 1,
but it will be extremely awkward to trace over an image of a site plan, not
only painfully slow and inaccurate, but also risky and unprofessional. Have
you really tried? Those plans have some difficult curves, it will be a
nightmare to trace it over, don't even suggest that.
Option # 2, importing a drawing; you bring a 3D wireframe of a site plan,
and then tell Revit to use that import to create the topography. Once
created, you may erase the imported drawing. Nothing wrong with that, if it
works.
The other option, # 3, is the one that works with the Lisp routine. This
option has the advantage that you don't need to import any CAD drawing,
which is what you and others are against to. All you need is some previous
work in AutoCAD before going into Revit. In AutoCAD, you need a 3D wireframe
of your site plan; have all the contours elevated as per the actual
elevations. Then, in AutoCAD, you run the Lisp routine. It only takes
seconds to generate a list of all the x,y,z coordinates of the first and
endpoint of every line or polyline segment. The routine saves the list in a
.txt file. Then close AutoCAD, go to Revit > Site view > Massing and Site
tab > Toposurface > Create from import > Specify points file > select the
.txt file created by the Lisp routine > and Voilá! ...your topography is
created in an instant. The result is accurate, since it is created with
actual coordinates. Now compare this with tracing over an image!
Alfredo Medina
Online training of
AutoCAD & Revit Architecture
www.planta1.com